Thread-cutting mechanism for sewing-machines.



No. 885,990. PATENTED APR. 28, 1908 G. S. GATGHELL.

THRBAD OUTTING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED FEB. 7, 1907.

2 SHEETSSHBET 1.

fiiiflm 1 W W.

ATTORNEY G. S; GATUHELL. THREAD CUTTING MECHANISM FOR SEWING MACHINES.

APPLIOATION FILED FEB. 7,1007.

IIVVEJIV Z [I 73% I rromvsr PATENTED APR. 28, 1908.

2 SHEETS-SHEET 2.

UNITE STATES PATENTOFFIOE;

GEORGE S. GATCHELL, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO THE SINGER MANUFAC-z TUBING COMPANY, A CORPORATION OF NEW JERSEY.

THREAD-CUTTING- MECHANISM FOR SEW1.NG-MIACIHIINTESv I Specification of Letters Patent.

Patented April 28, 19 08.

Application filed February 7, 1907. Serial No. 356,146.

T 0 all whom it may concern: Y

Be it known that I, GEORGE S. GATCHELL, a citizen of the United States, residing at Elizabeth, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in'Thread-Cutting Mechanism for Sewing-Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to an improvement in thread-cutting mechanism for sewing machines, and has for its object more particularly to simplify and render more effective the mechanismof this class forming the subject of the United States Patent No.

' 742,366, of October 27,1903.

The present improvement is designed particularly for embodiment in shank-button sewing machines of the wellknown Singer type, and in its preferred form comprises a button-holding and ositioning presser-foot carrying a normally Xed dipping member, a

stationary cutting member spaced therefrom and an interposed movable cutting and nipping blade mounted upon a rock-shaft and provided with apositive connection with the pattern-cam for controlling .the

button-feeder. The operative portion of the stationary cutting blade is arranged slightly beyond the corresponding portion of theset the stitch and simultaneously carrying a' loop of the same laterally around itself, prearatory to nipping the upper portion of such 00 after which it continues to slip over the en portion of the nipped thread until its lower edge severe the opposite end of such loopin conjunction with the stationary or ledger-blade. i

The machine is provided with a stop- Tnotion mechanism comprising a stoppingcam having the usual yieldingconnection with the driving or needle-actuating shaft formed with a peripheral camortion fikminating in a stop-notch adapte to be entered by theupper end of a spring-pressed plunger-rod carried by a swinging stop-lever. The presser-bar carries'the usua engaged by the forward end of a lifting lever fulcrumed intermediate its ends upon the rigid finger machine frame and having at its opposite end 1 a positive pivotal connection with one end of an actuating rock-lever carrying at its tained out of such operative relation by means of the usual latch-lever one'uend of which-lies in the path of a tripping-pin carried by the pattern-cam.. The timingof the parts is such that tlfe final engagement of the plunger-rod with its notch in the stoppingcam efiects the actuation of the presser-bar lifting lever to raise the presser-foot in oppo.

sition to its'spring which takes place immediately after the actuation of the cutting and nipping 'ijiechanism. In the present machine, thetopping-camj is provided with an 'abruptshoulder at the forward edge of its movements of the needle-bar frame and the mechanism is the lifting of the presser-foot which is insured to take place invariably after the thread nipping and cutting actions which can be effected only-While the patterncam is actually in motion.

The movable nippingand cutting blade is retracted from operative position after the first few initial stitches of a group have been formed, and its positive actuation by the pattern-cam insures such movement while the nedle is out of the Work, whereby any interference with the needle by imperfect timing is"prevented. While the movable blade is provided with positive actuating means one of its connections is preferably constructed with a safety device adapting its component parts to receive a relative yielding movement in case the blade should becdme cloggedor otherwise prevented by means of an obstructionfrom free action, thus insuring against breakage or disarrange ment of parts in the further operation of the machine until the obstruction may be removed, Y

The invention will be understood by reference to the drawings annexed, in which Figure '1, is a side elevation of one side of a Singer button sewing machine provided with the present improvement, and Fi 2 a similar eievation of the opposite si e thereof, with "a portion of the work-supporting arm in section. Fig. 3' is an end view of the patterncam and the cooperating member of the cutter-actuatingmechanism, and Fig. 4 is a detail view of a portion of the cutter-actuating mechanism showing artly in section the safety device. Fig. 5 1s a detail face view of the stopping-cam and the upper end of the plunger-rod of the sto -motion device. 6 is a detached side el evation of the presserfoot, carrying the thread-cuttin and nipping. members and Fig. 7 a simi ar view of the o posite side of the presser-foot. Figs. 8 an 9 are plan views of the presser-foot showing the movable cuttin and nipping member respectively in close and open positions. Fig. 10 is a bottom plan view of the stationary cutting blade and the movable cuttin and nippingblade in open or inoperative relation. Figs. 11 and 12 are sectional views illustrating res ectively the initial and finaloperations of t e thread cutting and nipping members upon the needle-thread. Figs. 3 to 12 inclusive are upon a larger scale I than Figs. 1 and 2.

The machine is constructed with .a frame comprising the base portion 1 having the cylindrical work-sup orting arm 2 and the bracket-arm 3, in W 'ch latter is journaled the driving shaft 4 carrying at its forward end the take-u cam-cylinder 5 with camgroove 6 entere by the stud 7 of the angular take-up lever-3 pivoted at 9 in the bracketarm and carrying the usual crank-pin connected by link 10 with the reciprocating needle-bar 11 carryingthe needle 12. The

"main-shaft 4 carries the pattern-cam cylincrank-arm 23 connected by means of a link' 24 with a lateral crank-arm 25 mounted upon one end of a second rock-shaft 26 having at its 0 posite end a depending crank-arm 27 to whic 1 is attached by universal joint connection a socket-member 28 of a link comprising a rod 29 also having a universal joint connecseaeee I tionby means of the intermediate block 30 with a crank-arm 31 of a verticalrock-shaft 32 'ou'rnaled in a fixed sleeve 33 in the forwardly projecting ortion 34 of the presserfoot 35, secured to t e lowerend of the presserbar 36 by means of the fastening screw 37. The lower edge of the portion 34 of the presserfoot provides the fixed jaw or member of the thread-nipping device, and is herein represented (see Figs. 6, 7, '11- and 12) as a ver tical blade 38 removably secured to the body of the presser-foot by means of a fastening screw 39. The. stationary thread-cuttingmember'or ledger-blade 40 is spaced slightly beneath the stationary nipping jaw, and in the intermediate space is arranged the movable nip ping and cutting blade 41'fiXed to the lower end of the rock-shaft 32. As represented in the drawings, the operative edge of this blade is slightly concaved at 42 present- 35 ing to'the thread a blunt operative portion with inwardly inclined faces in the form of a wedge. As represented more particularly in Fig. 10, the cutting edge of the ledgerblade 40 is substantially flush with the operative edge of thenipping jaw 38, but 1n its operative portion it is provided with a notch or recess 43 which is sharpened along the face ad'acent the path of movement of the movabie blade 41. By the provision of the notch or recess 43 in the ledger-blade, its operative portion is located slightly rearward of that of the stationary nipping jaw 38'as shown in Figs. 10 and 11, whereby the closing movement of the movable member 41 serves to move the needle-threadsuccessively into engagement with the nipping jaw and the ledger-blade. The operative ortions of the blades 40 and 41 are concave at 43 and 42, respectively, in order to insure the em gagement of the thread to be operated upon at the desired oint of these implements, While the operatlve portions of the members 38 and40 are disposed the one in advance of the other in reference to the movable mem- 11o ber 41 in order that the thread may be first firmly ni-p ed, and an extra length of thread provided beyond the nipped portion before the thread is actually severed, whereby the compressed portion of the thread is given an 115 increased resistance to pulling out by means of the adjacent uncompressed portion between the same and the cut extremity.

While the arrangement of the stationary nipping and cutting jaws 38 and 40 are de- I pendent upon the shape of the movable member 41 for their successive action in connection' with the latter as before described, they are in practice limited in such position by the concave button-channel 35 formed in the presser-foot 35 to aflord a guide-Way for the utton heads as they are successively delivred from the button chute 16 by the button-feeder 16 for the stitching operations.

'The ledger-blade is yieldingly secured in position upon the bottom of the presser-foot portion 34 by means of a. pair of stu -screws 44 assing upwardl through the same and soc ets formed in t e portion-34 and entering suitably threaded holes iii-"a thrust-plate I 45 intermediate which and the bottom of said sockets are interposed the springs 46 serving to produce a yielding upward pressure upon the ledger-blade 40. BK providtweent e ing a yielding connectionbe edger-- blade and the supporting presser-foot portion 34 accommodation is providedfor variations'in thickness of the needle-thread used observed that the member 28, 29, affords a positive and unyielding connection between the crank-arms 27 and 31, excepting in case the blade 41 becomes clogged orobstructedby any means, forcibly preventing the blade from assuming closed operative position, in which case the s ring 47 permits a yielding action between t 1e parts 28 and29, thereby preventing breakage of the normally positively actuated elements of the cutting and nipping mechanism. I

The main-shaft 4 is provided with the usual crank 48 with pitman connection 49 with the intermediate rocker 50 having slotted arm 51 embracing a crankin 52 upon the rearward end of the shutt e-actuating rock-shaft 53 having at its forward end the shuttle driver 54 engagin in a manner well known the shuttle 55 oscillating in the shuttle-race 56, and cooperating with the needle 12 in the production of stitches. The mainshaft 4 carries upon its rearward portion the loose pulley 57 and fast pulley 58 to which is yieldingly connected, by means similar to those of United States Patent No. 742,366 before mentioned, the stopping-cam 59 having the peripheral cam-portion 60 terminating in its higher operative portion in the notch 61 with abrupt shoulder 62. The cam 59 is adapted to be engaged by the reduced upper end of the plunger-rod'63 slidably mounted in the swinging stop-lever 64 pivoted at 65 upon a bracket 66 of the machine frame, such longer-rod being normally pressed u'p-" ward y by means of a spring 67 interposed between a boss 68 6f the stop-lever 64 and a collar 69 fixed upon the plunger-rod. The sto -lever is provided with the usual 'belt sh' ting arm 70 and is normallypressed rearwardly into operative position b means of s ring 71 interposed between t e same and i -der its momentum (the belt having been initudinally disposed socket .84 entered by a be held in retracted inoperative position- (as represented .m dotted in Fig. 1) by the hooked rearward end ef the latchg-lever 72; fu crume pon. a lag ?3 ii-the bracket-arm and having its ppposlte end lying'ingthe path of movement a tripping iii 74 proge'ct in o h pe ph y e P xwatn. cy inder 13f.-

The machine is set in motiqli by means of the treadleractuated rod 7 5;connectedwith a rilglid lateral arm 76' of the stop-lever 64, w ereb" the latter'is tilted backwardly and engaged by the lath-lever 72' until the atter istripped: by the pin 74, w vhen"the stop-lever- 64- isthrown backwardlyby its actuating spring 71 and the upper end of the plungerrod 63 shifted beneath the lower portion of the stopping-cam 59 upon,- which 1t rides in retarding the movement of the machine untially shifted to. the loose pulley ,57 in the stop ing-operation) until it passes over. the shou der 62and intc the peripheral notch 61, when the machine is brought to rest.

The presser-bar '36 is provided withta fixed collar 77 having a lateralfiiiger 78 which en-I gages the forward end of a lifting lever 79 fulcrumed upon the bracket-arrn at SO-and having upon its rearward end a lateral pin 81 entering a notch or fork in the forward end of an actuating rock-lever 82 fulcrumed upon the bracketarm at 83 and having its rearward end extending laterally behind theplunger-rod 63 and provided with a longishouldered latch-pin 85 surrounded by a spring 86 intermediate the rearward end, of said socket and theshouldered head of said. latch-pin, which latter is provided with a pair of lock-nuts 87 oneof which serves as a stop to limit the forward motion of the latchpin 85 under the action of its spring 86. A spring 88 is interposed between the rearward portion of the rock-lever 82 and the bracket 66 for yieldingly maintaining the same de- 10 pressed and the connected lever 79 in normal. inoperative position with its adjustable stopscrew 7 9 in engagement with the under side of the bracket-arm, while the presser-spring 89 bearing upon the collar 77 of the presserbar 36 serves to normallymaintain the presserfoot 35 in operative relation with the work.

l Vhen the stop-lever 64 is.in inoperative position, theplunger-rod with its collar 69 is withdrawn from operative relation with the latch-pin 85,but when shifted into operative position the side of the collar 69 first engages the end of the latch-pin 85fand temporarily forces the same inwardly, until the stopping.

cam 59 depresses the plunger-rod 63 to carry the collar 69 below the pin 85, as represented in full lines in Fig. 1, when the latter is enabled to spring outwardly above the collar 69. When the plunger-rod rises upon entert e frame of'the machine, but is adapted to 1 ing the cam-notch 61 carrying the collar 69 13c with it, the latter engages the lower side of the latch-pin 85 andrcarries upwardly with it the rearward end of the rock-lever 82 whose forward end is depressed, thus causing the rocking of the lifting lever 79 ,and the raising of the presser-foot. It will be observed that the operative portion 60 of the stopping-cam offers a positive barrier to the automatic thread engaging parts of the machine are so timed in their operative actions u on the thread that the nipping and cutting lade 41 commences its operative movement while the take-up S is stilf rising, and before the stitch is fully set. As the path of movement of the member 41 is crosswise of the thread leading fromthe work to the eye of the needle, its

engagement with the latter produces a bend therein and thus causes it to cooperate with the take-up in performing the setting action between the nipping parts and the work in the final stitch of a group in addition to its primary nipping and cutting actions. This is of considerable practical importance in the operation of the machine, as it insures the severing of the thread uniformly 'at tlie cutting edges and obviates the liability of the tearing apart of the thread at the nip ing shoulder of the member 38, which has 0 aractorizcd other cutting and nipping devices timed to act upon the thread after the stitchsetting has taken place and when the needlethread has become tightened to its fullest extent. hen the take-up is nearing its upper or stitch-setting position, as represcntcd for instance in full lines in Fig. 1, and before the stitch has been finally set, a small amount of slack still remains in the needlethe entire rendering of the thread leading abruptly around the edge of the blade 38 This action continues until the blade 41 has reached the cutting edge of the blade 40, the

drawing u of the thread between the member 88 an the work serving to perform the final setting of the stitch, while the continued movement bf the blade 41 serves to thrust the thread against the cutting edge of the member 40 to sever the thread. The parts abnormal resistances to are so timed that as the take-up reaches its highest position, represented in dotted lihes in Fig. 1, the lower edge of the blade 41 en- ;cam 13 must continue to operate so as to impart these cutting and nipping movements, and the cam-groove 19 is therefore so :disposed that the final cutting action takes place just prior to the entrance of the plunger-rod 63 into its cam-notch 61 in'stopping the machine; and the shoulder 62 of the cam 59 intermediate the cam portion 60 and notch 61 is made more abrupt than heretofore in order that the final rise of the plungerrod 63, and the consequent lifting. of the presser-foot, may be deferred until the completion of the thread-nipping and cutting ac ti on. As previously indicated, and as represented in Fig. 3, the form of the cam-groove 1.9 is such as to maintain the blade 41 in closed position for at least two or three stitches, so that upon the starting of the machine the severed e'nd of the needle-thread continues to be ni ped until one or more initial stitches have lleen formed by the stitchforming mechanism, after which the blade 41 is retracted into the osition represented in Fig, 9, while the need e iselevated above the same.

The button sewing machine shown and described herein comprises overseaming mechanism of the type in which the needle-bar is mounted in a swinging frame deriving its lat eral movements from a connection with the pattern-cam 13, but it is evident that the overseaming feature of the machine forms no part of the present invention.

-While' the preferred embodiment of the present improvement is shown and described herein, it is to be understood that the-present invention is susceptible of material modification in constructive details, and that the thread-cutter for severing the needle-thread after the formation of a grou'p of stitches, and operating means for said thread-cutter in- (7 her and a normally unyielding c ction adapted to transmit operative jfiOVGlHGHtS directly from said actuating member to the thread-cutter, said connection being adapted to yield under excess' e loads imposed. by

lee action of the cutter.

uding a positively driven actuating memsaid cam and it reciprocating threadecafryinghpeedle, and ya pattern cam for controlling t character of the stitches, of a thread-cutter forsevering the needle-thread after the: roduction of a group or succession of stito es, and a normally unyieldin connection intermediate threadcutter, which is adapted to transmit. operative movements directly from the one to the other andtoyield under abnormal resistances to the cutting o eration.

3. n asewing machine, the combination with stitch-forming mechanism including a reciprocating thread-carrying needle, and a pattern-cam for controlling the character of the stitches, of-a thread-cutter for severing the needle-thread after theproduction of a group or succession of stitches, and a normally' unyielding connection intermediate said cam and thread-cutter including two relatively movable members-having abutting portions and a spring for maintaining such abutting portions forcibly inxcontact relation, and means including a positive connection with one of such members for actuating said cutter to sever the needle-thread.

4. In a sewing machine, the combination with stitch-forming mechanism including a reciprocating thread-carrying needle, and a pattern-cam for controlling the character of the stitches, of a thread-cutter for severing the needle-thread after the production of a group or succession of stitches, and anormally unyielding connection intermediate said cam and thread-cutter including a link membercomposed of a socket and a headed rod embraced by the latter and maintained firmly seated therein by means of a spring, whereby said cutter is actuated to sever the needle-thread.

5. In a sewing machine, the combination with stitch-forming mechanism, a presserfoot and a thread-cutting and -nipping device carried by said presser-foot, of automatically acting means for actuating said thread-cut:

ting and nipping device for severing and nipping the thread, and automatically acting means operating independently of said actuating means for lifting the presser-foot after the thread-cutting and -nipping operation.

6. In a sewing machine, the combination with stitch-forming mechanism, a 'presserfoot and a thread-cutting and -nipping,de-

vice carried by said resser-foot, of'automat ically. acting means, includlng a cam for actuating said thread-cutting and :nipping de-- vice for severing and nipping the thread, and automatically acting means, controlled by said cam independently of said thread-cutting and nipping device, for lifting the resser-foot after the thread-cutting and -nipping operation.

7. In'a sewing machine,

the combination l ser foot, of a thread-cutting and -nipping dewith stitch-forming mechanism, a presser. foot, and a thread-cutting-and .-nipping device carried by said resser-foot, of automatically acting means for actuating said thread-cutting and -nipping device to cause itto severand nip the thread, a stopmotion device, means carried by said actuating means fortrippingsaid stop-motion device into operation, and a positive connection intermediate said stop-motion device and presser-foot whereby the latter is raised as the machine is stopped after the cutting and nipping operation,

8. In a sewing machine, the combination with st1tch-form1ng mechanism, a presserfoot and a thread-cutting and nipping de vice carriedby said presser-foot, ofautow,

matically acting means, including a cam, for actuating said thread-cutting and -nipping device for nipping and severing the thread, a stop motion device including a peripherally notched rotary stopping-cam and a reciprocating plunger-rod cooperating therewith,

means carried by said cam for tripping the stop-motion device into action-in stopping the machine, anda positive connection intermediate said presser-foot and plunger-rod whereby the. final action of the latter under the control of the rotary stopping-cam effects the, lifting of the presser-foot."

9. In a sewing machine, the combination with stitch-forming mechanism, a stop-motion device for controlling the period of op eration of thesame, a presser-foot and a thread-cuttirigand nipping device carried by said presser-foot, of automatically acting means independent of said stop-motion'device for actuating said thread-cutting,and nipping device for nipping and severing the thread, independently. acting means for lifting the presser-foot, and means positively connected with and controlled by said stopmotion device whereby the operation of t e pre'sser-foot lifting means is effected at the end of the final stitch-forming operationof a series and after the thread has been nipped and cut. I v

10. In a sewing machine, the combination with a stitchforming mechanism, including a reciprocating thread-carrying needle and a reciprocatory take-up member acting uponthe needl'ethread, of a thread cutting and nipping device acting" successively to first nip and then sever the needle-thread, means foractuating the take-up member-in setting thestitches, and means for actuating the thread-cutting and -nipping device while the take-up member is completing its action 1 upon the thread to first draw off and nip the thread during the final action of the take-up member and thereafter sever the thread at the completion of said take-up action.

11. In a sewing machine, the combination with stitch-forming mechanism, and, a presping and cutting blade with-double-wedgeshaped 0 erative'ed e, and means for actuating sai movable b ade to engage the thread and deflect the same beneath the nipping blade and thereafter carry the same to the stationary cutting blade for severing it.

12. In a sewing machine, the combination With stitch-forming mechanism, includin a reciprocating thread-carrying needle, an a presser-foot, of a thread-cutting and nipping device carried by said presser-foot and com prising a fixed nipping member, a Ciyieldingly mounted ---cutting member space beneath the same, and an intermediate movable cutting and ni ping blade adapted to engage the needle-t read and carr it first to the fixed nipping member and then to the yieldingly mounted cutting member, and means for actuating said movable cutting and'nipping blade.

scenes 13. in a sewing machine, the combination with stitch-forming mechanism, includin a reciprocating thread-carrying needle, an a presser-foot, of a thread-cutting and -nipping device, carried by said resser-foot and comprising a fixed nipping member, and a nor-- mall stationary. cutting member'spaced beneat the same, a thrust-plate disposed. above said resser-foot, a plurality of guide-pins for connecting said cutting member and thrust-plate, s rings for pressin said thrustplate upward y, and a pivotaly mounted cutting; and nippingblade intermediate said stationary nipping and cutting members, and means for actuating said cutting and nipping blade to carry the thread successively to the stationary nipping and cutting,

members.

In testimony whereof, I have signed my- 

